Spotlight keeps changing to picture.

I know how to change the lock screen back to Spotlight but why after several days does it revert to picture. I have been using Spotlight for many years and this has only just started happening. Does anyone know why this has suddenly started occurring?

This happened to me on a new build for no particular reason. Try this fix Reset and Re-register Windows Spotlight in Windows 11 Tutorial

That didn't work for me so I started using use the Dynamic Theme app to set up Spotlight.

Thanks for the info, much appreciated, will give it a try.